You asked me if there is a site where you can practise the pronunciation of irregular verbs. GOOD NEWS! I've been surfing the net and here you are: click here.
You can download an app for your mobile phone (android).

In this post you have a couple of presentations and exercises for this grammar point.

BBC is great to learn English: here you are some videos to revise the past simple. You can read the script at the same time as you listen if you find them difficult (some of them are not very easy). Pay special attention to pronunciation. And answer the comprehension questions.

Pronunciation of regular verbs is a nightmare, isn't it? Try to do these quizzes. (Me parece que hay un problema en la página y no se pueden corregir online pero podéis verlo en las útilmas páginas de esta copia) Don't worry if you make mistakes with "t" and "d", for me that is not important. If you don't make mistakes when you choose "id", that's perfect.